Pellet mill



S. A. OLIVER Aug. 1 l, 1953 PELLET MILL Filed May 29, 1948 2 Sheets-Sheet l Snvgntor attorney 1953 s. A. OLIVER 2,648,296

PELLET MILL Filed May 29, 1948 2 Sheets-Sheet 2 Q 3nnentor 5NN7 A. UL IVA-7? attorney Patented Aug. 11 1953 UNITED STATES PATENT OFFICE PELLET MILL Sennet A. Oliver, Montebello, Calif.

Application May 29, 1948, Serial No. 30,089

11 Claims.

This invention relates to a machine for producing pellets from a mash or-mixture of stock feed and for like purposes. More particularly, this invention deals with a mill for producing feed pellets for consumption by rabbits raised for food.

Rabbits, more particularly, if fed food pellets that are too long, will bite off part of a long pellet and drop the remainder. The sanitary screen flooring provided in rabbit hutches permits such dropped pellets to fall out of reach of the animal and is, therefore, wasted. Thus, it is important to provide pellets of a size acceptable to the animal and it is an important object of this invention to provide a pellet mill that can be accurately controlled, while the same is in operation, to obtain pellets of a desired size.

A pellet mill of the nature herein contemplated embodies a perforated die ring and one or more rolls within the ring for pressing mash into and through the perforations of the die ring. The high speed of the rolls results in their hammering against high spots of said ring should there be any inaccuracies in the mounting of the rolls relative to the ring and/or to each other. Another object of the invention is to provide novel means that effects a common adjustment among all the rolls mutually, whereby they roll smoothly along the inner face of the die ring irrespective of whether said inner face is truly circular or not to thereby eliminate the heretofore objectionable hammering that deleteriously affected both the die ring and the rolls.

A further object of the invention is to provide, in a pellet mill, novel means sealing off the mashreceiving chamber to obviate mash falling therefrom during operation of the machine, said means yet permitting free and frictionless high speed rotation of the roll or impactor means that extrudes the mash through the die ring.

My invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawings merely show and the following description merely describes one embodiment of the present invention, whichis given by way of illustration or example only.

In the drawings, like reference characters designate similar parts in the several views.

Fig. 1 is a partly broken plan view of a pellet mill according to the present invention.

Fig. 2 is an enlarged plan sectional view of the mill, said view being taken on line 2-2 of Fig. 3.

Fig. 3 is a side elevational view, in quarter section, of said mill.

Figs. 4 and 5 are fragmentary detail sectional views showing structural features of the mill.

Fig. 6 is a fragmentary cross-sectional View on line 6-6 of Fig. 1.

The pellet mill that is illustrated comprises, generally, a stationary frame l0 that mounts a fixed die ring H, a rotary impactor unit |2 mounted in the frame and having operative engagement with said die ring, hopper means l3 carried by the impactor unit for feeding mash into a chamber M encircled by the die ring, cutter means If: for severing pellets extruded through the die ring by the impactor unit, a pellet-receiving annular chamber I6 surrounding the die ring, a drive H for the impactor unit, and a variable speed drive I8 for the cutter means.

The mill frame l0 comprises a support plate l9 from which upwardly extend a plurality of parts 20 that space a ring 2| from said plate IS. The central opening 22 in ring 2| is somewhat smaller than the inner diameter of die ring I the latter being mounted on ring 2| and located between an annular lip 23 on the latter ring, and a second ring 24 bolted to said latter ring as at 25. The lip 23 and ring 24 serveto center the die ring on opening 22.

Means 26 is provided for fixing the die ring to ring 2|, said means comprising a plurality of like elements uniformly spaced around said latter ring. Because of the forces involved that seek to rotate the die ring, each element of means 26 comprises a sleeve 21 slidingly fitted in a bore in ring 2| and having a conical end 28 extending into a conical seat provided in the bottom edge of the die ring. Said conical end 28 is firmly urged into its seat by a spring 29 that is retained by a collar 30, a nut 3| engaged with said collar, and a stud 32 extending through sleeve 2! and threaded into the die ring. It will be seen that by taking up on nut 3|, spring 29 is loaded to exert an end pressure on sleeve 2'! to press its conical end 28 into its seat. The several such elements provided insures a firm non-displaceable fastening for the die ring.

The die ring II is generally conventional for the type of mill herein disclosed, is provided with a multiplicity of die orifices 33, arranged in plural rows, through the wall thereof, and, in practice, has its inner face 34 and its outer face 34a machined for respective engagement with the impactor unit I2 and the cutter means l5.

' The impactor unit I2 is mounted on a central shaft 35 that rotates in a bearing 36 fixed on 3 support plate l9 and residing between said plate and ring 2|. Thus, the portion 31 of shaft 35 that projects upwardly from hearing 36 is relatively short and lends accuracy to th impactor unit carried by said shaft. A relatively heavy plate 38 is keyed to the portion 31 of said shaft and forms the sturdy support member for said impactor unit. Said plate 38 constitutes the bottom for chamber [4 and, in practice, an annular extension flange 39 is fastened thereon and extends as close as practicable to the wall of a counterbore 46 formed in Opening 22. The plate 38 and its flange 39 are thus freely rotatable in opening 22, there being no friction involved.

As contemplated herein, the small annular space M between flange 39 and counter-bore 46 is filled with a lubricant of low viscosity so that the same will not readily flow. As shown at 42, said lubricant will receive a coating of the mash material in the chamber l4 to provide an adequate seal that prevents mash from falling through annular space 41. The lubricant can be introduced through a suitable number of passages 43 each fitted with a self-closing pressure fitting 44.

The impactor unit I2 is shown as comprising three pairs of similar plates of each of which plate 45 is the lower and 46 the upper, a pivot bolt 41 for each pair of plates 45 and 46 and threaded into plate 38, at the bottom, and into a top plate 48 parallel to said plate 38, and an impactor roll 49 carried by and mounted between each pair of plates 45 and 46. Each roll 49,-by

means of suitable anti-friction bearings 56, rolls on a stud that ties the free ends of the plates 45 and 46 together. In this manner, each pair of plates 45 and 46 and the roll 49 carried thereby comprises a frame that is swing-able on pivot bolt 41. Fig. 2 clearly shows this arrangement wherein the frames are uniformly arranged about the axis of rotation of the impactor unit.

As best seen in Fig. 3, the necessary lubricant provided for bearings 56 is prevented from contaminating the mash in chamber l4 by labyrinth seals 52 provided between stationary and rotational parts of the roll mounting means.

The present mill is designed for clockwise rotation. Although a reverse arrangement would be effective, it is preferred to have the rolls 49 travel in advance of. their respective pivots 41 and, by rolling engagement with inner face 34 of the die ring, effect a gathering of mash against said face and then a forcing of the mash through the orifices 33. As the rolls progress at high speed, their continuous engagement with the die ring will result .ina continuous and rapid extrusion of the mash through the orifices.

While the rolls will be centrifugally forced into engagement with the die ring, positive means is provided for effecting uniform pressure of all three rolls against the die ring irrespective of such variations that there may be in the form of said die ring and in the mounting of the rolls. To this end, each lower plate is provided with. a beveled edge 53 and each upper.plate.4 6'

with a similar but oppositely beveled edge 54,.,

and a cam Wedging unit 5 5;is provided centrally or axially of the mill to engage said beveled edges and thereby press the rolls simultaneously against the die ring.

Said unit 55 comprises a rod 56, a fixed conical cam 51 that engages ;the beveled edges of the three lower plates45, a. relatively movable conicalcam on said rod that engages the beveled edges of the three upper plates 46, and resilient take-up means 59 on the rod for exerting a pressure to urge the cams 51 and 58 toward each other. In this manner, the rolls 49 mutually and simultaneously are outwardly pressed. It will be noted that the means 55 has no fixed position but rather floats in a position centrally 0f the roll frames. Consequently, the same is free to shift in any direction to find a position of adjustment that is controlled by the three points of contact between the die ring and the three rolls. Thus, should the rolls vary in size among themselves, they would yet be adjusted bythemeans .55 to have uniform rolling engagement with the die ring. It will be evident, therefore, that the three rolls, bodily, and notwithstanding the fixed pivot bolts 41, will accommodate themselves within the die ring, regardless of whether the face 34 of thelatter is truly round or not.

The pressure of earns 51 and 58 may tend to flex plates 45 and 46 inwardly toward each other. To counteract this, a sleeve 66 is strung over rod' 56 to serve as a spacer for said plates. Said sleeve, of course, floats with the rod and, accordingly, is formed with flanged ends 6| for ample bearing engagement with said plates.

The hopper means 13 comprises a conical member 62 that is mounted on top of plate 48, the base of said member being smaller than the diameter of said plate to define a peripheral ledge 63. This ledge, in advance of each roll 49, is provided with a passage 64 through which mash, fed to the conical member 62 and directed thereby to the ledge, falls into the chamber [4. Thus, almost immediately, the mash is compressed between the rolls 49 and the die ring to be extruded through the orifices of the latter. An upper annular extension 65 is provided for the diering to cooperate with the ledge 63 for enclosing passages 64 and also to retain from spillage ,of mash as the same descends toward said passages.

The means I5 is provided for severing the extruded mash to form them into pellets as contemplated herein. As shown, means I5 comprises a plurality of uniformly spaced blades or cutters 66 that are angularly directed toward and havingosliding or wiping engagement with the outer facea34a of the die ring. In the present mill, the cutters are mounted to rotate in the same direction as the impactor unit [2.

Each cutter 66 is carried by a bracket 61 and said brackets are mounted on a pulley 68 that, through the medium of a bearing ring 69, rotates on the annular extension 65 that is fixed to the die ring. The cutters are arranged so that their leading or cutting edges sever the pellets as they are extruded. I I

The several pellets fall into annular chamber 16, the same being formed by a ring plate 76 that is a horizontal extension of ring 24 and an annular wall ll extending upward from the outer peripheral edge of said ring plate. One or more discharge openings 12 may be provided in chamber.. -l6, and one or more blades 13 may be mounted, as on brackets 61, to shovel the severalpellets so they fall through discharge opening..or openings 12. It will be noted that wall H extends considerably above the orifices 33 and, in practice, is made as high as practicable to insure that none of the severed pellets fiy outward of chamber IS.

The drive I! for the impactor unit [2 comprises a grooved pulley 14 on shaft 35 for a plurality of V-belts 15, and an electric motor 16 having a smaller grooved pulley 11 over which said belts are trained. This drive effects a uniform rotational speed of the impactor unit and remains constant unless the speed of the motor is changed.

The variable speed drive I8 is provided for controlling, while the mill is in operation, the size of the pellets produced thereby. Temperature conditions, variations in the material comprising the mash and other factors may contribute to variations in the speed of extrusion of said mash through the die ring. Said variations may occur even during a continuous run of the mill. Inspection of the pellets produced is readily accomplished by sampling them as they are severed. If too short or too long, the means I8 is quickly adjusted to change the speed of rotation of the cutters accordingly.

As shown, the drive l8 includes the mentioned pulley 68 which is grooved for a V-belt 18 that is trained over a smaller pulley 19 of a speed reducer 80. The latter is provided with a pulley 8| over which is trained a V-belt 82 that extends around a tapered flange expansion pulley 83 of a varidrive unit 84. This unit is provided with a second tapered flange expansion pulley 85 on th same shaft with pulley 83 and with means 88 that is manually adjustable to simultaneously bring closer together the tapered flanges of either pulley 83 or 85 and, correspondingly, separate the tapered flanges of the other. By shifting handle 86a of means 86 relative to plate 86b, the flanges of one pulley ar separated and the flanges of the other are correspondingly brought together. A V-belt 81 is mounted on pulley 85 to be driven from an electric motor 88. The above spreading and contracting of the pulley flanges enlarges the are of contact of one belt 82 or 81 and diminishes the other, thus varying the drive transmitted from motor 88 to pulley 8!. Suitable tension means 89 may be provided for each belt 82 and 81 to automatically take up slack in one or the other of said belts as the unit 814 is adjusted. One such tension means 89 is shown in Fig. 6, the other being similar. The unit 84 is one of several such devices that are available on the open market and requires no further explanation, except that the means 86 is adjusted in one direction to enlarge the effective operativ size of pulley 83 and contract the effective operative size of pulley 85 to speed up rotation of the cutters, and in the other direction to contract the effective operative size of pulley 83 and enlarge the effective operative size of pulley 85 to slow up rotation of the cutters.

In the construction of the varidrive umt 84, the outer flanges of pulleys 83 and 85 are fixed on their shaft and the inner flanges of said pulleys are connected to each other and slidable by manipulation of handle 86a. The inwardly directed faces of the flanges of the respective pulleys are oppositely tapered to receive V-sectioned belts 82 and 81. Reference 1S made to the inner two pages of the four-page catalogue of Standard Transmission Equipment 00., Pasadena, California, and titled Standard Trans missions, which was filed in this application with the amendment of June 4, 1952. In said catalogue it is seen that by moving control handle 88a the shaft and pulleys are moved toward or away from motor 88 or pulley 8|, resulting in tension on one belt 82 or 81 and slack on the other as the tapers of the pulley flanges are adjusted to give a new ratio between the effective or running diameters of said pulleys.

This mutual compensation of pulley sizes and belt tensions gives the mentioned speed variations and controls desired.

In this manner the speed of the cutters 6 6 can be adjusted while the mill is in operation. to ob- 1. In a mill of the character described having,

a stationary di ring with material-molding. orifices extending therethrough, an impactor'unit rotatably mounted within said die ring and comprising a plurality of swingable frames each having an impactor roll engaged with the inner face of the die ring to press material into and through said orifices and a floating unit embodying wedge means located centrally of the frames to engage all of them simultaneously to urge the rolls into rolling engagement with the inner face of the die ring.

2. In a mill of the character described, having a stationary die ring with material-molding orifices extending therethrough, an impactor unit rotatably mounted within said die ring and comprising a plurality of swingable frames each having an impactor roll engaged with the inner face of the die ring to press material into and through said orifices, each frame including upper and lower plates above and below the roll thereof, a floating unit having a wedge in common engagement with all of the upper plates and a wedge in common engagement with all of the lower plates, and means embodied in said floating unit for adjusting the wedges relatively to urge said upper and lower plates of the frames in a direction to press the rolls thereof into rolling engagement with the inner face of the die ring.

3. In a mill of the character described, having a stationary die ring with material-molding orifices extending therethrough, an impactor unit rotatably mounted within said die ring and comprising a plurality of swingable frames each having an impactor roll engaged with the inner face of the die ring to press material intoand through said orifices, each frame including upper" and lower plates above and below the roll thereof,

a floating unit having a wedge in common engagement with all of the upper plates and'a wedge in common engagement with all of the lower plates and resilient means engaged with one of said wedges and embodied in said floating unit for adjusting the wedges relatively to urge said upper and lower plates of the frames in a direction to press th rolls thereof into rolling engagement with the inner face of the die ring.

4. In a mill of the character described having a stationary die ring with material-molding orifices extending therethrough, an impactor unit rotatably mounted within said die ring and comprising three symmetrically arranged rolls each engaged with the inner face ofthe die ring, three frames each having upper and, lower portions and mounting each roll, a pivot for each QQQIQQQ:

prising (three symmetrically arranged v rolls, each engaged with the, inner face ofthe die ring three H frames each; having 'upper and lower portions andniounting eachr'olL' a pivot for each frai ne, a rotatable plate .for ,pivotally supporting the ends of 'said pivots, and centrally disposeclcam;

wedging means for simultaneous engagement withfthethreejrames to ,urge "the. same to swing on their respective pivots' and thereby pressthe rolls into. rolling en agem t with the die rin said cam 'wedging means including spaced conicalwedges, one engaging the. upper and the 0ther the lower portions of the frames, said conical wedges being relatively adjustable.

6. In a mill of thechara'cter described, having a stationary'die ring with materiahmolding orifices" extending therethrough, an impactor unit rotatablyrnounted within said die. ring and comprising a plurality of. swingable. frames each having animpac'tor roll engaged with the inner face of the (lie ring'to pressmaterialinto and through said orifices, each frame including upper and lower plates above and belowthe roll thereof a floating unit ha-ving'a wedge incominon engagement withall of theilpper plates and a wejdg'e' in"co'mm on, engagement with all of the lower plates "means embodied in said floating 40 unit'for adjusting the wedges relatively to urge said "upper "and lower. plates of the framesin .a direction to pressIthe' rollsthereoi into rolling engagement With the innerlface of the die ring, andmeahsconcentric with said floating unit and between the wedgeslthereof for spacing. the upper andlo'wer plates of theiframes.

7'. In a inill'ofthe character.des cribed, haV-;- ing a stationary die ring with material molding orifices. extending therethrough, anaimpactor unitfrotatably mounted within. said. die'ring and comprising. a plurality. of swingable frames each having. an'iinpactor. roll, engaged with the inner face of the die'ring. to press'fmat'erialpinto and through .said orifices, each frame including... 5 upper and lower plates above andfbelowthe roll thereof afioating unit having a -wedgein 90m mon engagement with allYofthe upperaplates and a wedge in commonengagementwithallof the. lower plates means embodiedfin jsaid iioatc0 ing'funit for adjustingthe wedgesrelatively to urgesaid ,up'per andlower plates of theframes I in adirect'ion to press the rolls thereof.intohrolh ing'. engagement with 'the inn'er face of the die ring, and means concentric with said floating unit andfbetweerfthe wedgeslthereof'for spac-v ingthe'i ppr and lowerpla'tesbf theirames, saidv latter fmeans comprising'ja sleevel having, upper and lower flanges for respective engage;

mentfwith the under face of the upperplatesandflo the upper face of the lower plates..

8. 'In a mill or the character'described, a ma-. terial-molding diering, a fixed ring mounting the'sar'ne and having a central opening, a rotatablc impactor unit extending throughwsaidgs en ng a mb0dyi e..- s e a e th t e. inner- .face of the die ring and a circular plateemhodied; in said unitand provided with aring flange spaced from the wall of said opening; to define an annular space, said fixed ring, having a passage extending therethrough and opening,

intosaid annular space and adapted to conduct low viscosity lubricant to fill said1 annular space and, .thereby seal the chamber defined by said;

die ring and circular plate.

9. A mill of the characte described comprisinga die ring,; impa ctor means forpressing material. through-the die ,ring fromthe inside through the. outsidethereof, means. for rotating said impactormeans at a constant speed, cutter meansforsevering the materialextruded from the die ring to form pellets, and variable speed drive means;

forrotating thecutter means relatively tothe die ring to control the length ofsaid pellets,,.said,

latter means comprising an electric motor, and an adjustable drive connection between said mow tor and the cuttermeans, said adjustable drive. connection: embodying a pair of pulleys and;

means for simultaneously increasing the effective operative size ofone of said pulleys andder creasing the effective operative size of the other.

10. A mill of the character described comprisid. p l t adi l tter e nsc mplii i an ctric motor, a unit embodying a pair of variable pulleys and means for simultaneously; enlarging; the effective size of onepuiley and reducing the effective size of the -other, a drive connection from the motor to one of said pulleys, and-a drive connection fro m the other pulley to the cutter means.

11. A mill of the character described'comprising a die ring, impactorrmeans for pressing material; through the die ring from theinside through the outside thereof, means for rotating id impactor m a t a n an rs eed, te

means for severing ,the material extruded from the die ring to form pellets, and variable speed drive means for rotating. the,cutter means relatively to the die ring toeontrolthe length of said p lets id l te m a s-.c nr nea e ct motor,-a unit embodyinga pair of variable pulleys; and means for, simultaneously enlarging the effective size of one pulley and-, educing theeffective size of the other, .a drive connection from the motor to one pf said pulleys, a speed reducing unit,; a drive connection fromthe other pulley to the speed; reducing;unit -anda drive -connection fromthe'latter unit to the cutter means.

SENNET A. OLIVER.

References, Citedin the file of this patent;

UNITED STATES; PATENTS Number. Name Date 2,124,744 Me akin- July 26, 1938 2,157,528 Crabtree May 9, 1939 2,160,302 Billows May 30, 1939, 2,177,132 Crabtree Oct. 24, 1939 2,240,660 Meakin May s, 1941 2,241,556,, Evenstacl May. 13, 1941 2,279,632 Meakin Apr. 14, 1942 2,295,743- Meakin Sept. .15, 1942' 

